Which metal reacts with steam when it is red-hot?

 Which metal reacts with steam when it is red-hot?

A. gold

B. iron

C. copper

D. platinum

E. silver

The correct answer is B. iron

Explanation:   

This question is referring to the reactivity of metals with water in the gaseous state called steam. Different metals react differently with water, and some metals only react with water when they are heated to a high  temperature.

metallic iron reacts with steam only when it is heated red-hot. When steam comes into contact with red-hot iron, a chemical reaction take place, producing iron(III) oxide and hydrogen gas. 

The words equation for this reaction is 

Iron + steam ->iron(III)oxide+hydrogen 

The chemical equation for this reaction is: 

3Fe(s)+4H2O(g)→Fe3O4(s)+4H2(g).

In the other way round, metals such as copper in Option A and gold in Option D are less reactive metals and do not react with steam, even when they are heated red-hot. Sodium in Option B and calcium in Option C are more reactive metals and can react with water at room temperature, therefore, they don't need to be red-hot to react with steam.

To answer questions like this you need to understanding the reactivity series of metals which is essential in predicting how different metals will react with various substances, including water in the form of steam. This is an important concept in the topic "electrode potentials, electrochemical series, electrolysis" in chemistry, and  is often tested in exams.

QUESTION SOURCE: NECO CHEMISTRY 2001 QUESTION 31